/* Locking note:
* Implement POSIX locks in terms of BSD flock locks.
* This at least gets distributed whole-file locking to work.
* Strategies for distributed record locking will deadlock.
*/
Npfcall*
diod_lock (Npfid *fid, u8 type, u32 flags, u64 start, u64 length, u32 proc_id,
Npstr *client_id)
{
Fid *f = fid->aux;
Npfcall *ret = NULL;
u8 status = P9_LOCK_ERROR;
if ((f->xflags & XFLAGS_RO)) {
np_uerror (EROFS);
goto error_quiet;
}
if (flags & ~P9_LOCK_FLAGS_BLOCK) { /* only one valid flag for now */
np_uerror (EINVAL); /* (which we ignore) */
goto error;
}
if (_fidstat(f) < 0)
goto error_quiet;
switch (type) {
case F_UNLCK:
if (flock (f->fd, LOCK_UN) >= 0) {
status = P9_LOCK_SUCCESS;
f->lock_type = LOCK_UN;
} else
status = P9_LOCK_ERROR;
break;
case F_RDLCK:
if (flock (f->fd, LOCK_SH | LOCK_NB) >= 0) {
status = P9_LOCK_SUCCESS;
f->lock_type = LOCK_SH;
} else if (errno == EWOULDBLOCK) {
status = P9_LOCK_BLOCKED;
} else
status = P9_LOCK_ERROR;
break;
case F_WRLCK:
if (flock (f->fd, LOCK_EX | LOCK_NB) >= 0) {
status = P9_LOCK_SUCCESS;
f->lock_type = LOCK_EX;
} else if (errno == EWOULDBLOCK) {
status = P9_LOCK_BLOCKED;
}
break;
default:
np_uerror (EINVAL);
goto error;
}
if (!((ret = np_create_rlock (status)))) {
np_uerror (ENOMEM);
goto error;
}
return ret;
error:
errn (np_rerror (), "diod_lock %s@%s:%s",
fid->user->uname, np_conn_get_client_id (fid->conn), f->path);
error_quiet:
if (ret)
free (ret);
return NULL;
}
/* Locking note:
* Implement POSIX locks in terms of BSD flock locks.
* This at least gets distributed whole-file locking to work.
* Strategies for distributed record locking will deadlock.
*/
Npfcall*
diod_lock (Npfid *fid, u8 type, u32 flags, u64 start, u64 length, u32 proc_id,
Npstr *client_id)
{
Fid *f = fid->aux;
Npfcall *ret;
u8 status = P9_LOCK_ERROR;
if ((f->flags & DIOD_FID_FLAGS_ROFS)) {
np_uerror (EROFS);
goto error_quiet;
}
if (flags & ~P9_LOCK_FLAGS_BLOCK) { /* only one valid flag for now */
np_uerror (EINVAL); /* (which we ignore) */
goto error;
}
if (!f->ioctx) {
msg ("diod_lock: fid is not open");
np_uerror (EBADF);
goto error;
}
switch (type) {
case P9_LOCK_TYPE_UNLCK:
if (ioctx_flock (f->ioctx, LOCK_UN) == 0)
status = P9_LOCK_SUCCESS;
break;
case P9_LOCK_TYPE_RDLCK:
if (ioctx_flock (f->ioctx, LOCK_SH | LOCK_NB) == 0)
status = P9_LOCK_SUCCESS;
else if (errno == EWOULDBLOCK)
status = P9_LOCK_BLOCKED;
break;
case P9_LOCK_TYPE_WRLCK:
if (ioctx_flock (f->ioctx, LOCK_EX | LOCK_NB) == 0)
status = P9_LOCK_SUCCESS;
else if (errno == EWOULDBLOCK)
status = P9_LOCK_BLOCKED;
break;
default:
np_uerror (EINVAL);
goto error;
}
if (!((ret = np_create_rlock (status)))) {
np_uerror (ENOMEM);
goto error;
}
return ret;
error:
errn (np_rerror (), "diod_lock %s@%s:%s",
fid->user->uname, np_conn_get_client_id (fid->conn),
path_s (f->path));
error_quiet:
return NULL;
}
static void
test_rlock (void)
{
Npfcall *fc, *fc2;
if (!(fc = np_create_rlock (1)))
msg_exit ("out of memory");
fc2 = _rcv_buf (fc, P9_RLOCK, __FUNCTION__);
assert (fc->u.rlock.status == fc2->u.rlock.status);
free (fc);
free (fc2);
}
